The HP-18 is a Richard Schreder-designed metal Racing Class sailplane that was offered as a kit for homebuilding during the 1970s and 1980s
Design and development
The HP-18 is a flapped (15-meter) sailplane featuring a V-tail and 90-degree flaps for glide path control. The fuselage is composed of a prefabricated composite forward fuselage and a semi-monocoque aft fuselage and features steeply reclined seating and a side-stick controller although modifications using a conventional stick have been made.
Very low cockpit with a reclining seating position
Sidestick (changed to conventional stick by some homebuilders)
Two-piece canopy (changed to single piece forward opening by some homebuilders)
V-tail that folds upwards for easy storage
Wing structure composed of spars with caps pre-machined from solid aluminium plate and aluminium wing skins bonded to closely spaced foam ribs
Fibreglass fuselage pod, wingtip skids and tail fairings
Aluminium tail cone
Winglets added by some homebuilders
Water ballast carried inside the hollow aluminium wing spars
Typical Schreder trailing edge flaps/airbrakes partially interconnected with the ailerons.
As most homebuilds, the HP-18 has been constructed with many variations in detail. Perhaps the most significant version is the Super HP-18 developed by Canadians Ed Hollestelle and Udo Rumpf, which features a modified wing airfoil, winglets, a front-hinged canopy, conventional control stick and higher ballast capacity.
Crew: One pilot
Length: 23 ft 2.4 in (7.07 m)
Wingspan: 49 ft 2 in (15.00 m)
Wing area: 113 ft2 (10.5 m2)
Aspect ratio: 21.4
Empty weight: 470 lb (213 kg)
Gross weight: 970 lb (446 kg)
Maximum speed: 150 mph (240 km/h)
Maximum glide ratio: 38
Rate of sink: 126 ft/min (0.6 m/s)